Hyderabad: Supplements may lower efficacy of select drugs

Common adverse events show nutritional deficiencies.

Hyderabad: Dietary supplements are becoming part and parcel of many patients’ lives but they are found to lead to adverse events due to the interaction between drugs the patient may be taking and the supplement. The effects are not often known to clinicians and are also less understood. It is always important to understand the contents of a supplement in terms of chemicals and micronutrients.

According to rough estimates, 67 per cent of patients with cancer, 77 per cent with osteoporosis and 34 per cent with non-communicable diseases take at least one dietary supplement. A random study in hospitals found that 61 per cent of senior citizens were on dietary supplements and most of these were self-prescribed.

Dr Sai Kumar Katam, national president of the Doctor of Pharmacy Association, says both drug and nutritional therapy are critical for patients, but “the potential for drugs and nutrients to interact with each other is significant but unrecognised by many physicians. These interactions are found to be the reason for therapeutic failure and also adverse effects of the drugs. It has also been found that alterations in the nutritional status of the patient impacts the outcome of the treatment.”

Studies carried out at hospital level show that the interaction of supplements with drugs is an important factor in understanding the reasons for adverse drug effects. Supplements marketed for diabetes and control of blood sugar are found to have hypoglycaemic effects. Similarly, the use of glucosamine and turmeric in osteoarthritis patients is found to interact with drugs results in anti-coagulants.

Dr G.S. Rao, senior physician, explained, “The use of supplements is found to be safe and effective in maintaining a healthy body but when there is a non-communicable disease then the potential interaction with prescribed medications has to be considered. We have found instances where the interaction of the medicine with the nutrient has not resulted in the efficacy of the medicine as required. The evidence collected points to re-looking at supplements in a scientific manner.”

The interplay between drugs and nutrients can result in alternation of pharmacokinetics (the branch of pharmacology concerned with the movement of drugs within the body) and pharmacodynamics (the branch of pharmacology concerned with the effects of drugs and the mechanism of their action). Also, the interaction can either increase or decrease the absorption of nutrients by the body. Common adverse events noted in clinical studies have shown nutritional deficiencies, drug toxicity, loss of therapeutic efficacy or disease control, and unwanted physiological changes.

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